Magnetic hard disk drives and other types of spinning media drives such as optical disk drives are well known. In a typical hard disk drive, the part that holds the read/write head over the correct data track on the spinning data disk, is called the suspension. The suspension typically includes a base or baseplate that is affixed to an actuator arm, a spring portion or simply a “spring” attached to the base, and a beam portion or load beam attached at the end of the spring. The beam portion has a flexure attached to it. The flexure typically has a stainless steel metal support layer, an insulating layer such as polyimide, and a conductive layer made of copper or copper alloy. The insulating layer and the conductive layer form circuitry on the metal support layer. The flexure has a fixed portion that is fixed to the load beam such as by laser spot welding, and a gimbaled portion or simply a gimbal. The gimbal holds the head slider which contains the read/write data transducers, and allows that head slider to pitch and roll freely as the data disk moves underneath the head slider which allows for slight irregularities in the data disk surface and for vibrations in the disk. The slider is maintained at the correct height over the spinning disk platter via an air bearing created by the wind due to the spinning disk.
In a dual stage actuated (DSA) suspension, in addition to the voice coil motor which moves the entire suspension, an actuator located somewhere on the suspension effects fine movements of the head slider for fast, accurate positioning of the head slider. DSA suspensions have been proposed that mount one actuator, or usually two piezoelectric actuators acting in push-pull fashion, on the base plate, on the load beam, or on or acting directly on the gimbaled portion of the flexure. Such actuators are sometimes called milliactuators, or microactuators especially if the actuators are located on, or act directly on, the gimbal. Suspension designs in which a microactuator is mounted on the gimbal, or acts directly on the gimbal, are sometimes called gimbal actuated suspensions, or GSA suspensions.
Piezoelectric devices are often made of lead zirconate titanate (PZT), although other materials exhibit piezoelectric properties and are sometimes used to make piezoelectric devices. The term “PZT” is often used as shorthand to refer generally to piezoelectric devices. That shorthand terminology will be used herein, it being understood that a “PZT” device need not be strictly made of lead zirconate titanate.
U.S. Pat. No. 9,129,624 issued to Hahn et al. and assigned to the assignee of the present application, discloses a GSA suspension having PZT microactuators that extend from a relatively fixed part of the flexure to the head gimbal, i.e. to the gimbaled portion of the flexure, through flexible ribbon-like connectors. That patent is hereby incorporated by reference in its entirety for the flexure structure including the connections between the piezoelectric microactuators and the gimbal.
As the demand continues for ever greater track densities and read/write speeds, a need remains for lighter, faster, and more responsive DSA suspension designs.